Dextran sulfate sodium (DSS) colitis in rats - Clinical, structural, and ultrastructural aspects

Aim of this study was to assess the structural, ultrastructural, immunohist ochemical, and clinical aspects in Sprague-Dawley rats with dextrane sulfat e sodium (DSS)-induced colitis. Colitis was induced in Sprague-Dawley rats by seven days of DSS oral administration followed by seven days of tap wate r only (for one, two and three cycles). Controls were fed with water only. Segments of proximal, mid-, and distal colon of each animal were adequately prepared for light and scanning electron microscope observations. The seve rity of the lesions was scored histologically, For immunohistochemical stud y, a cocktail of S-100, NSE, and anti-neurofilament antibodies was used. Sy mptoms such as weight, feces consistency, diarrhea, hematochezia were recor ded daily, From a clinical point of view symptoms appeared significantly la ter after the first cycle than after the second and third cycles and lasted significantly longer in the second and third cycles. Treated rats showed a slower weight gain rate by 20% compared to controls, and the whole colon l ength appeared to be significantly shorter after colitis induction compared to controls. Structural observations by light microscopy showed prominent involvement of the distal colon. Immunohistochemical study of both submucos al and myoenteric nerve plexuses was similar to controls. Scanning electron microscope observations of the colonic mucosal surface in colitis rats sho wed a complete subversion of its architecture, characterized by dilatations of gland crypt openings, dropout of goblet cells, and inhomogeneous distri bution or lack of microvilli, These were most evident after the third cycle . In conclusion, experimental DSS colitis in SD rats appeared to be highly reproducible and shared most features with human UC, not only from a struct ural and clinical but also from an ultrastructural point of view.